Combustion apparatus



NOY. 10, 1953 H, C, MAY ET AL 2,658,462

CoMBUsToN APPARATUS 'original Filed April 2o, 194s Maximum Fu el 525 Fuel Figi

ATTQITloN CHAMBER l :mg. 2 25 501 515 l f E 55455 tg 4 557 516 INVENTOR.

55.5 Harry O. May

By EHQLZ A 7' TORNEY Patented Nov. 10, 1953 atan CMBUSTION APPARATUS Harry C. May, East Mcleesport, and Ellis E.

Hewitt, Pittsburgh, Pa., assignors to Westinghouse dir Brake Company, a corporation of Pennsylvania Original application April 20, 1948, Serial No.

22,208. Divided and this application September 24, 19%, Serial No. 117,700

2 Claims.

This invention relates to combustion apparatus, and more particularly to apparatus for controlling supply oi pulverized fuel and/or oil to a combustion chamber, the preser invention being a division oi our copending application, Serial No. 22,208, filed April 20, i948 and now Patent No. 2,568,127.

AThe principal object or" the invention is the provision of improved apparatus iol' controlling supply of pulverized coal and/or oil toa commisu tion chamber.

Other objects and advantages will become apparent from the following more detailed descrip-l tion of the invention.

In the accompanying drawing; Fig. l is a schematic view, partly in outline and partly in section, of control apparatus embodying the invention associated with combustion apparatus to be controlled; Fig. 2 is a vertical-sectional view or" a relay valve device comprised in the control apparatus shown in Fig. l; Fig. 3 is a vertical-'sectional view of a self-lapping valve device comprised in the control apparatus shown in Fig. 1; and Fig. 4 is a similar view of a magnet valve device comprised in the control apparatus shown in Fig. 1.

Description Crushed coal particles for the equipment are stored as a source of supply of fuel such as a nrst storage tank. 3 which is replenished by supply through a conduit 9 and a centrifugal type separator device it by means of a suction air stream. The separator device lil is provided for separating the crushed coal from the conveying air, and a centrifugal type suction fan (not shown) may be provided to create suction for moving said conveying air.

From the nrst storage tank t, which may be at slightly less than atmospheric pressure, the crushed coal stored therein is fed into a pressurized coal storage tank 2t which may be at a pressure of one hundred iifty pounds, for example. Coal pumps 2l are arranged to be driven by electric motors 22 for feeding the crushed coal from the storage tank s at low pressure into the storage tank it at higher pressure. Detail of the coal pumps is not shown, but said pumps may be in the form oi a rotatable element having a cavity formed therein arranged to ll with coal when exposed to the tank 8 and to drop said coal upon subsequent exposure to tank 2t.

Crushed coal in the pressurized coal storage tank 2t is fed by a worm feed 23 into a line 24 adapted' to receive compressed air at say one hundredzity pounds from a source (not shown).

2 An electric motor 25 is provided for driving the worm feed 23.

Pulverized coal thus fed into the line 2d is conveyed by the compressed air flowing therein into a coal feed regulator device 26 which is adapted to regulate the supply of air-conveyed coal from the line 2li to a feed line 2l', by-passing any excess back into the storage tank 2li.

The regulator device 2t may comprise a feed valve 2i) and a by-pass valve 3d, both substantially in the shape of a frustrated cone or modified iorm of needle valve, connected one with the other by a rigid element 3 l. A stem 32 may be secured at one end to valve 3G and reciprocably disposed within a suitable bore in a sleeve member il@ for guiding movement of the valves. An operating stem 34 may be provided for actuating the valves 29, 30. The opposite end of stern 3d may be disposed outside the casing of device 26 for pivotal connection to an operating lever of an actuating device, as will be described in detail hereinafter. Movement of stem 3ft moves valves 29 and 30 toward or away from respective valve seats 3l and 38, according to direction of such movement. As valve 29 is moved toward seat 3l by upward movement of stem tl, valve 3l) is simultaneously moved away from seat 38. Line 2li opens into a supply chamber it intermediate the two valve seats, while feed line 2l is open to a delivery chamber il on the outlet side of seat 3l, with a return chamber l2 on the outlet side of seat 38 opening into the top of tank 2t. The airconveyed Coal supplied to chamber fill is distributed to chambers il and i2 in accordance with proximity of the valves 2S and Si@ to the respective seats 3l and 33, as will be appreciated.

The air-conveyed coal flowing in feed line 21 is expanded through an adjustable nozzle device @3, where the pressure drops from one hundred fty pounds to about seventy pounds, into a conical attrition chamber llt. The compressed air which has permeated into the pores of each coal particle while passing through line '2l cannot escape rapidly enough to instantaneously attain the pressure in the attrition chamber, after passing through the nozzle device and so it shatters the coal into tiny fragments. The use of a conical attrition chamber after the nozzle device 43' TheV absence made adjustable to allow the air-to-coal ratio to be maintained at a suitable vaiue as the coal ow varies, The conveying air to line Z4 is supplied by such as a booster compressor (not shown which may be driven by such as a variable speed turbine (not shown), whereby the pressure at the inlet to nozzle device 43 will tend to vary with speed of the booster compressor which is substantially dependent upon the amount of fuel supplied, but by adjustment of the flow area of said nozzle device the proper pressure drop therethrough may be maintained for any given amount of fuel and supply of conveying air to line 21, as will be more fully described hereinafter.

The adjustable nozzle device 43 may comprise a casing having an inlet chamber 48 to which the feed line 21 is connected, and an outlet chamber 49 connected to the attrition chamber 44. A Variable area throat may be formed intermediate the chambers 48 and 4S by an element 5i! fixed to the interior of the casing in the path of flow of coal and conveying air admitted to chamber 4S, and by an adjustable element 5| projecting into said path of flow opposite to element 5i). Adjustable element 5| may comprise a cylindrical portion slidably mounted in a suitable bore in the casing and attached to an operating rod 53 extending outwardly through the casing; the outer projecting end of rod 53 being adapted for pivotal connection to an actuator, as will be described in detail hereinafter, to position the adjustable element 5|.

The atomized coal and conveying air leaves the top of the attrition chamber 44 and, via a pipe 54, enters a by-pass control valve device 55, which, during normal running operation of the plant, connects said pipe 54 via another pipe 5S to a nozzle device 51 for introducing the ne particles of the coal from tank 8 to a combustion chamber device 58. The by-pass control valve device 55 is operative, during starting of the combustion chamber with fuel oil, as will be later described, to disconnect the pipe 56 from the pipe 54 and to connect the latter pipe to a return pipe 59 connected to the top of the iirst storage tank 8. Thus, during starting, any coal and/or conveying air supplied to the feed line 21 by-passes the combustion chamber device 53 and is returned to the storage tank while said combustion chamber is warmed up on an oil flame, as will be pointed out.

The by-pass control valve device 55 may ccmprise a casing G in which is disposed a piston slide valve or the like, having an inlet port 62, which is constantly open to the pipe 54 from the attrition chamber 44, and two separate outlet ports 53, 64 connected to port 62, may be provided for registry with pipes and 59, respectively. In a first position of the valve 5|, port 63 registers with pipe 5S while port 8d is blanked off, and in a second position, the port 63 is blanked off and port 64 registers with the return pipe 59. A compression spring 55 may be arranged to urge valve 6| in the direction of its first position, and by supply of iiuid under pressure to a chamber 66, action of said spring may be overcome to move said Valve to its second position. Upon venting of fluid under pressure from chamber 5B, the spring S5 returns valve 5| to its first position, in which it is shown in the drawing.

A second nozzle device 61 is provided for introducing fuel oil to the combustion chamber device 58 for warm-up of the turbine (not shown) during starting and for supporting a pilot llame to assure combustion of coal during running operation of said turbine. Associated with nozzle device 61 is a fuel oil flow control element, such as a needle valve 61a, adjustable to different positions to regulate flow of fuel from a source independent of tank 8, such as a fuel oil supply tank 61h, through said nozzle device to the combustion chamber device 58. By advancing the needle Valve 51a toward a seat 61C, the amount of fuel oil to the combustion chamber device 58 is reduced. By moving valve 61a away from seat 51e, the amount of fuel oil to chamber device 58 is increased. A stem 51d is provided to allow for adjustment of the needle valve 61a. One end of stem 61d is attached to the needle valve, while the opposite end is adapted to be connected to an actuator device for effecting the adjustment of said valve, as will be described hereinafter.

A fluid pressure actuator device 315 is provided for positioning the coal feed regulator device 2G, and a similar iiuid pressure actuator device 311 is provided for positioning the adjustable nozzle device 43. Both actuator devices 315, 311 are adjustable in accordance with variations in pressure of fluid in a control line 318 common to both devices for simultaneous positioning of devices 26 and 43.

For adjusting position of the needle valve 61a of nozzle device 61 to control supply of fuel oil to the combustion chamber device 58, a fluid pressure fuel .oil nozzle control actuator device 45 is provided. An operators control valve device 406 is provided for controlling supply of fluid under pressure to the actuator device 405. A relay valve device 401, responsive to pressure of fluid from the operators control valve device 455, is operable to effect supply of fluid under pressure to the by-pass valve device 55 and to a normally closed uid pressure switch device 408 for stopping motor 25 to prevent coal from being fed into the feed pipe 21 during warmup with fuel oil, as will be described hereinafter. A magnet valve device 459 is provided for controlling supply of fluid under pressure to the operators control valve device 406.

A starting switch 4|@ is provided for controlling supply of electric current from a source of electrical energy such as the battery 3D0 to the magnet valve device 4639, and the various electric motors in the plant, as will be described hereinafter in detail.

The fluid pressure actuator device 316, 311, 495 may comprise a hollow cylindrical casing 4|2 containing a piston 4|3 slidably mounted therein which is subject to pressure of fluid in a chamber 4|5 at its one side and to pressure of fluid in a chamber 4| 6 at its opposite side. Chamber 4|5 is open to a port 4|1 in the casing, which, in the present instance, is open to the atmosphere. A compression control spring 4|9 is disposed in chamber 4|5 and arranged to urge the piston 4| 3 in the direction of chamber 4|6 toward a rest position seated against a projecting portion of an end wall 425 secured to the casing. A piston rod 420 is attached at its one end to the piston 4| 3 for movement therewith, and at its opposite projecting end outside the casing is pivotally connected to an operating lever 42| for positioning same. An opening in the casing accommodates the rod 420 which is slidable therein.

The operating lever 42| is pivotally connected at its one end by a pin 424 to a projecting arm M3 attached to casing 4|2. The opposite end of lever 22| is provided with a slot to accommodate a pin or the like for operative connection to a device or element to be positioned.

The operating lever 42| of actuator device 315 is operatively connected to stem 34 of the coal feed regulator device 20, While lever 42| of the actuator 311, which is similar to device 315, is operatively connected to the rod 53 of the adjustable nozzle device 43. The respective chamber M3 of both actuator devices 315, 311 is connected to the control line 318 Which is common to both of said devices.

In both the actuator devices 316, 311, upon supply of fluid under pressure to the chamber 09S therein, the piston 4|3 will move in the direction of chamber 4|5 against action of spring M9, and through rod 420 attached to said piston, will adjust position of lever 42| according to degree of movement of the piston. Piston 4|3 will move in the direction of chamber 4|5 until the fluid pressure force on its one side balances the force of spring ils on its opposite side, and this in turn will depend on the degree of pressure of the fluid supplied to the chamber MB. Upon subsequent reduction in pressure of fluid in the chamber M6, the piston will move in the direction of said chamber by action of spring di@ a distance dependent upon the degree of said reduction, with a resultant repositioning of the lever 22|. It will thus be seen that lever 42| will be caused to assume an angular position closer to or further away from the casing of the actuator device in accord with the degree of pressure of the iiuid in the chamber 4| 6.

Variations in pressure of fiuid eected via the control pipe 313 simultaneously in the respective chambers 250 in both devices 310, 311 effects simultaneous adjustment of the position of the respective levers 22|. As iiuid under pressure in chamber dit in actuator device 316 is increased through consequent positioning of the operating stem attached to lever 42|, the valves 29 and i0 in the coal feed regulator device 2G are positioned to increase the amount of coal supplied to the feed line 21 and reduce the amount of coal returned to the tank 20. As the pressure of fluid in the-chamber 4I of the actuator device 316 is decreased, through the lever 42| and stem 34 the valves 29 and 30 are positioned correspondingly to decrease the amount of coal to the feed line 2l, and hence the combustion chamber 58 and return the balance to the tank 20. The amount of coal supplied to the feed line 21, is thus varied in accordance with pressure of fluid in the control line 323, increasing as pressure of uid in said line is increased and decreasing as pressure of iiuid in said line is decreased.

in similar manner, increase in pressure of fluid in the chamber eilt of device 311, through lever 52|, positions rod 53 and adjustable element 5| in nozzle device i3 to increase the flow area at the throat. Decrease in pressure of fluid in chamber @I3 in actuator device 311 causes adjustment of rod 33 and adjustable element 5| in nozzle device 43 to decrease the throat area of said nozzle device. An increase in coal and air supply to the fuel line 21 calls for an increased throat area in the adjustable nozzle device d3, while a decrease in coal and air in fuel lines 21 calls for a decrease in said throat area, in order to maintain the proper pressure drop through said nozzle device. For this reason, the coal feed regulator device 23 and the adjustable nozzle device 23 arev positioned simultaneously in ac- 6 cordance with variations in pressure of :duid in the control line 318.

In the starting portion of vthe control apparatus for the plant, the fluid pressure actuator device 603 for adjusting position of the needle valve -device t1 is similar to the actuator device 316. Device 205 is responsive to variations in pressure of duid in a control pipe 5|3 connected to chamber di@ therein to adjust position of needle valve 31a in device 61. As pressure of fluid in chamber di@ is increased from a minimum value of ten pounds to a maximum value of sixty pounds, for example, the actuator device 505 will respond to vary position, through lever 42| and stem 51rd of the needle valve 31a from a substantially closed position to a fully open position for accordingly varying the amount of fuel oil supplied from pipe 31h through nozzle device 61 to the combustion chamber device 58 from a minimum amount to a maximum amount. When pressure of fluid in control pipe 5|3 is at its minimum value, ten pounds for example, the needle valve `i''d, will be disposed a slight distance away from its seat 31o to allow a certain quantity of fuel oil to flow to the combustion chamber to support a pilot flame for assuring combustion of coal supplied to said chamber during running of the plant after warm-up with the oil. Graduated increase in pressure of iiuid in control pipe 5|3 will cause graduated increase in amount of fuel oil supplied to the combustion chamber device 58 for Warm-up or" the plant during starting thereof. During starting, the turbine shaft is rotated by a starting motor (not shown) while the fuel oil is burned in the combastion chamber for warm-up until such as a turbine (not shown) develops suflicient power to be self-operating and is taken off the starting motor and operated on the fuel oil.

ri'he control pipe 5|3 is connected to the delivery chamber 204 of a self-lapping valve portion 5M of the operators control valve device 406.

Referring to Fig. 3, the self-lapping valve portion 5M of the operators control Valve device 406 may comprise a casing 202 having a supply chamber 203, a delivery chamber 204, and an exhaust chamber 205 therein. A supply valve seat element 20G, attached to operating stem 200 for movement therewith, is adapted for reciprocable movement within the casing 202. Element 206 is open at one side to the supply chamber 203 by way of ports 201 and a cavity 208, and at its opposite side to the delivery chamber 204 by way of a supply valve seat 200. A supply valve 2|0 in the form of a ball may be disposed within cavity 208 for controlling communication between the supply chamber 203 and the delivery chamber 204. A bias spring 2li is disposed in the cavity 208 for urging the valve 2|0 toward a normally closed position on seat 200. An exhaust valve seat element 2 l2, secured for reciprocable movement lwith a diaphragm 2|3, is open at one end to the delivery chamber 204 by way of an exhaust valve seat 2|!! formed therein. Valve seat element 2|2 extends through the diaphragm and opens into the exhaust chamber 205 by way of a central opening 2|5 extending from end to end. An exhaust valve 2l5 connected to the Supply valve 2|0 by a pin 2|0 and in the form of a ball is disposed in delivery chamber 204 to cooperate with the seat 2|4 in element 2|2 for controlling communication via opening 2|5 between said delivery chamber and the exhaust chamber 205. A bias spring 2 3, disposed in the delivery chamber 204, may be interposed between seat elements 206, 2|2 for biasing the seat element 206 in the direction of chamber 203. The diaphragm 2|3 is subject on one side to pressure of fluid in a diaphragm chamber 2 Il, which pressure of iiuid is that of the delivery chamber 204, the two chambers being connected one to the other by Way of a choke 2|8. The opposite side of the diaphragm 2l3 is exposed to atmosphere in the exhaust chamber 205, said exhaust chamber being open to the atmosphere by way of a port 2 i9 in the casing. A compression control spring 220 is disposed in the exhaust chamber 205, interposed between the diaphragm and an adjustable spring seat element 22|, for determining the degree of deflection of said diaphragm for any given pressure condition in the delivery chamber 204. The adjustable spring seat 22| is provided to allow for changing the precompression of the control spring 220.

In operation of the self-lapping valve portion 5|4 of operators control valve device 403, when operating stem 200 is moved inwardly of the casing 202 a certain distance and held there, the attached seat element 209 is moved downwardly, as viewed in the drawing, while the supply valve seat 209 formed in the end of element S is moved away from the supply valve 2|0. At this time supply valve 2|0 will remain stationary due to seating engagement of the attached exhaust Valve 2|5 on seat 2|4 of element 2|2. supply valve seat 209 moves away from the supply valve 2|0, supply chamber 203 is opened to delivery chamber 204 by way of the ports cavity 200 and seat 200. Fluid under pressure supplied to the supply chamber 203 from any suitable source will then flow into the delivery chamber 204 where the pressure of iiuid will thus be caused to increase. Pressure of iiud in diaphragm chamber 2V! will increase with that in the delivery chamber 204, the former chamber being open to the latter by way of choke 2|S. Pressure of fluid in diaphragm chamber 2|?, being greater than the atmospheric pressure in chamber 205 will deflect diaphragm 2|3 against action of spring 220 in the direction of the last named chamber. Deflection of diaphragm 2|3 will carry the exhaust valve seat element 2|2 with it. Bias spring 2|| will cause the supply valve 2|0 and exhaust valve 2I5 to follow movement of element 2|2, while said exhaust valve remains seated on seat 2! 4 in the end of said element, until said supply valve seats on seat 209 in element 206. Upon seating of the supply valve 2|0, the supply chamber 203 is closed to the delivery chamber 204 and further increase in pressure in the last named chamber thereby will be prevented. In absence of further increase in delivery pressure in the diaphragm chamber 2|?, the pressure force on its one side will balance with spring force on its opposite side and further deection of said diaphragm will cease. The supply valve 2|0 and the exhaust valve 2 I5 remain seated. If, at this time, stem 200 were moved inwardly a greater amount, element 200 would again be moved downwardly to unseat from the supply valve 2|0, the above described action would repeat, and an increase in pressure of fluid would be secured in the delivery charnber 204. The pressure of fluid thus obtained in the delivery chamber 204 will vary in substantial proportion to the degree of inward movement of the operating stem 200. The minimum pressure which will be held in the delivery chamber 204 will depend on the degree of precompression of the control spring 220 which may be changed by After the adjusting position of the spring seat element 22| Ii', subsequently, the operating stem 200 is allowed to be moved outwardly of the casing by action of spring 2|S to a more extended position, the supply valve 2|0 and attached exhaust valve 2|5 will be carried with it. The exhaust valve ZIE is thus unseated from seat 2|4 in element 2|2 and the delivery chamber 204 thereby opened by way of opening 2|5 in said element to exhaust chamber 205. Delivery pressure in chamber 204 is thus caused to reduce, and such reduction, reflected in the diaphragm chamber 2|'|, allows the control spring 220 to deflect the diaphragm 2|3 upwardly. Upward deflection of the diaphragm 2|3 carries the element 2|2 into engagement with the exhaust valve 215. The delivery chamber 204 is thus closed off from the exhaust chamber 205 and further reduction in delivery pressure prevented. The diaphragm 2|3, therefore, ceases further deflection, and both the supply valve 2|0 and exhaust valve 2 I5' remain seated. A reduced delivery pressure, determined by position of the operating stem 200, is thus secured.

Summarizing action of the self-lapping valve portion 5|4 of the operators control valve device 400, it will be seen that with the proper adjustment of spring 220 and with uid at adequate pressure in chamber 203, the pressure of fluid in the delivery chamber 204 will vary in accordance with position of element 206 as determined by position of the attached stem 200. For example, assume that the chamber 203 is connected to a source or iiuid at a pressure of sixty pounds, and it is desired to vary the delivery pressure in chamber 204 in a range between ten pounds and sixty pounds. The spring 220 may be adjusted so that with element 206 in a rest position, ten pounds will be established in delivery chamber 204, and as said element is positioned equal increments in the direction of said chamber by depression of stem 200, the pressure of iluid in said chamber is graduated in correspondingly equal increments until sixty pounds is reached. In the present example, that is, as long as the pressure of iiuid in supply chamber 203 is as great as the maximum pressure desired in the delivery chamber 204, the pressure of uid in said delivery chamber is determined by position of stem 200.

The supply chamber 203 in portion 5|4 of device 403 is connected to a supply pipe 5|5 which is adapted to be supplied with fluid under pressure via a delivery chamber in the magnet valve device 400 when energized.

Magnet valve device 409 may be of a wellknown type comprising a magnet portion 332 shown in outline, and a valve portion shown substantially in cross-section. The valve portion may be provided in the usual manner with a supply chamber 333, delivery chamber 334, and an exhaust chamber 335.

A normally closed supply valve 33? disposed in chamber 333 is provided for controlling communication between the supply chamber 333 and the delivery chamber 334. A normally open release valve 338 in chamber 335 controls cornmunication between the delivery chamber 334 and the exhaust chamber 335. A bias spring disposed in the supply chamber 333 is arranged to urge the supply valve 337 toward its closed position and at the same time urge the release valve 338 toward an open position, in which position the two valves are shown in the drawing.

In magnet valve device 409, its supply chamber 333 is connected to a source of fluid under pressure such as a reservoir 516 adapted to be charged by a compressor (not shown) to furnish fluid under pressure before the plant is started. When magnet valve device 499 is deenergized, supply pipe -515 is connected to the atmosphere via pipe 3136, and when device 499 is energized, said pipe 515 is connected to reservoir 516.

The operators control valve device 496 also comprises an operating portion for adjusting position of the stem 200 in the self-lapping valve portion 514 for effecting the variations in pressure of fluid in control pipe 513. The operating portion may be provided with a cam 511 adapted to be rotated about a fixed point 518 by an operators handle 519. A casing may be provided secured to the self-lapping valve portion 515 to carry the cam 511 and handle 519. Handle 519 may project outwardly through a suitable slot formed in the casing. Opposite ends of the slot may dene the opposite eXtreme limits of travel for movement of the handle 519, and these limits may represent Minimum Fuel, in which position it is shown in the drawing, and Maximum Fuel, respectively. The cam 511 is so shaped that by moving the handle from Minimum Fuel position towards Maximum Fuel position the self-lapping valve portion 514 is rendered responsive to effect an increase in pressure of fluid in control pipe 513 to call for more fuel oil to be supplied from nozzle device 61 to the cornbustion chamber device 53. Conversely, by subsequent movement of handle 519 back toward Minimum Fuel position, calls for a reduction in amount of fuel oil to the combustion charnber, accordingly.

Referring to Fig. 2, the relay valve device 551 may comprise a casing 243 having a diaphragm 244 disposed therein subject to pressure of fluid in a diaphragm chamber 245 on one side and to pressure of fluid in a chamber 246 on its opposite side, which latter chamber is open to the atmosphere via a port 241 in the casing. Also formed in the casing are chambers 24B, 249 and 259, chamber 24B being separated from chamber 246 by a partition 251 and from chamber 259 by a partition 252. A partition 253 separates chambers 249 and 2511. A valve 254 is disposed in chamber 256 for controlling communication between said chamber 256 and the chamber 259. 254 may be secured to a fluted stem 255 slidably mounted in a suitable bore extending through the partition 253, a seat 251 being formed in one end of said bore to accommodate said valve. A bias spring 253 is disposed in chamber 255, arranged to urge the valve 254 in the direction of seat 251. A valve 259, similar to valve 255, may be disposed in chamber 248 for controlling communication between said chamber 248 and the chamber 259, which latter chamber may be considered to be a delivery chamber. For slidably guiding valve 259, a fluted stem 265 is provided which is slidably disposed in a suitable bore opening through partition 252. A valve seat 262 is provided, formed in partition 252 for accommodating the valve 259. Stems 255, 265 project into and meet in the chamber 249 in such a manner that action of bias spring 259 on valve 255, in urging same in the direction of its seat 251, at the same time, through said stems, urges valve 259 in a direction away from seat 252. lf valve 259 is seated, valve 255 is consequently unseated. Valve 259 is operatively connected to the diaphragm 2M by means of a rod or stem 263 extending therebetween through a bore in par- Valve r titon 251 in which said rod is slidably disposed. A sealing ring may be provided in partition 251 for slidable sealing engagement with rod or stem 263 to prevent leakage of ud under pressure past the stem from chamber 248 and to chamber 246. A control spring 266 in chamber 246, arranged to oppose deection of diaphragm 244 in the direction of chamber 255 as caused by pressure of fluid in chamber 255, is provided for determining the degree of said pressure necessary for effecting operation of valves 255, 259.

In relay valve device 491, diaphragm chamber 255 is connected to the control pipe 513, chamber 255 is connected to atmosphere via a pipe 359, delivery chamber 249 is connected to a control pipe 525 which is in turn connected to the pressure switch device 465, and to chamber 66 in by-pass valve device 55, while chamber 250 is connected to supply pipe 515.

When the control pipe 513, and hence the diaphragm chamber 245 in relay Valve device 461, are pressurized, the diaphragm 244 is deflected in the direction of the chamber 256 so that valve 259 is seated and valve 254 unseated. With valve 259 seated, and valve 254 unseated, delivery chamber 259 is closed to chamber 258 to atmosphere and open to chamber 259.

When the control pipe 513 and the diaphragm chamber 255 of relay valve device 491 are not pressurized, the diaphragm 244 will be disposed in a rest position in which it is shown in the drawing, with valve 259 open and valve 255 closed. The delivery chamber 249 therefore is then closed to chamber 259 and open to atmosphere via chamber 258.

When pressure of fluid in control pipe 513 is increased above its minimum value a certain amount by movement of handle 519 in the control valve device 596 out of Minimum Fuel position, dur-ing starting of the plant, the relay valve device 591 will respond to pressure of fluid in said pipe 513 to connect the control pipe 529 to supply pipe 515 to open the switch device 496 and to move the piston slide valve 51 in by-pass valve device 55 to its second position, as previously defined for by-passing any coal and/or air supplied to the pipe 54 back into the tank 8 via pipe 59.

When handle 519 is in Minimum Fuel position, that is, when pressure of fluid in pipe 513 is consequently at a minimum, the relay valve device 551 will respond to such pressure to connect control pipe 529 to atmosphere via pipe 336.

The normally closed pressure switch device 593 is interposed in a wire 521 connected between one pole of battery 396 and one pole of the motor 25, the opposite pole of said motor being connected to the opposite pole of said battery by way of the wire 551 and starting switch 1116.

When the switch 516 is closed, which will be the rst thing to be done upon starting the plant, the terminals of battery 369 are connected to the wires 551 and 521. With the pressure switch device 395 normally closed in response to depressurization of the control pipe 529, the circuit including the closed switch 416 and wires 361, 521 is established between battery 995 and the motor 25 to operate same for feeding coal from tank 26 into the pipe 25. Upon movement of handle 515 in the control valve device 196 out of Minimum Fuel position, for supplying fuel oil to the combustion chamber device for warm-up, it will be seen that through consequent operation of the relay valve device 491 the control pipe 526 will become connected via device 491 to the charged supply pipe 5I5 and hence become pressurized. The pressure switch device 458 will respond to such pressurization of control pipe 520 to disestablish the above dened electrical circuit to terminate operation of motor 25, thus preventing any supply of coal to the feed line 21, while the by-pass valve device 55 connects pipe 54 to pipe 59, so that while the combustion chamber device is being warmed-up on fuel oil, any coal and/or combustion air flowing in pipe 54 will be returned to tank 3.

When it is desired to operate the combustion chamber device 53 on coal, the handle 5 l 9 may be backed off toward Minimum Fuel position for reducing pressure of fluid in pipe control 513. When pressure of fuel in control pipe 513 reaches a certain value, the relay valve device 401 will respond to cut-off control pipe 520 from supply pipe 555 and to connect said control pipe 520 to atmosphere. to its normally closed position to start up the motor 25 for supplying coal to the pipe 24 in which conveying air will now be flowing, and the by-pass valve device 55 is then allowed to return to its first position to connect coal and conveying air flowing in pipe 54 to pipe 56 for supply to the combustion chamber device 58. Coal thus supplied at this time to the combustion chamber may be burned along with a relatively great amount of fuel oil from nozzle 61 to assure proper combustion of said coal. The handle 5| 5 in control valve device 485 may then be returned to Minimum Fuel position for cutting supply of fuel oil down to a quantity sufficient to support a pilot iiame in the combustion chamber 58.

Subsequent control of supply of coal to the combustion chamber device is then effected through variation in pressure of uid in the pipe 315 as previously described.

A normally closed switch 525 may be opened or closed to disestablish and establish the electrical circuit, including in series the battery 300, magnet valve device 09 and switch 4H), to control supply of energizing current to the magnet valve device i523 accordingly. Opening switch 525 enables magnet valve device 459 to be deenergized to vent supply pipe 5I5 to atmosphere and thereby render the operators control valve device 556 ineffective to operate actuator device 455, thus preventing an unintentional increase in supply of fuel oil, other than the pilot supply, to the combustion chamber device 53 by accidental movement of handle 519 in control valve device 406 during operation of the combustion chamber on coal.

Summary From the foregoing description, it will be apparent that, according to one interpretation of the invention, the reservoir 5 l 6 may be considered to be a source of iiuid under pressure, the battery 350 may be considered to be a source of electrical energy. The fuel oil tank @1b may be considered to be a source of fuel oil, and the tanks 8 and/or 20 may be considered to be the source of pulverized coal. Since the source of fuel oil 51h and the source of pulverized coal 5 are independent and there is one of each source, and since both are sources of fuel, same may be considered to be two independent sources of fuel. Since the pipe 24, regulator device 26, feed line 21, device 53, chamber 44, pipe `54, valve device 55 and pipe 56 act to convey coal to the nozzle device 51, same may be considered t0 be fuel conveying means to convey fuel to one of said The switch device 458 then returns s nozzle devices. The worm feed 23 driven by motor 25 may be considered to be motor operated feeder means for feeding fuel from one of said sources of fuel to the conveying means 24, 2S, 21, etc. The control pipe 5|3 might be considered to be a first -control pipe to distinguish over the control pipe `520, which latter might be referred to as a second control pipe. The actuator device 465 including valve `61a associated with nozzle device 61 might be referred to as fuel liow regulating means for regulating flow of fuel from the other of said sources of fuel 6112 through the other nozzle device 61, between a maximum and a minimum amount in response to variation in pressure of fluid in said iirst control pipe 5|3 between a maximum and a minimum pressure, respectively. The operators control valve device 406 might be referred to as an operators control valve device employing fluid under pressure from the supply pipe 5I5 to effect the variation in pressure of fluid in the first control pipe 5 l 3. The pressure switch device 458 might be referred to as a pressure switch device responsive to establishment and disestablishment of pressure in the second control pipe 520 to disestablish and establish, respectively, an electrical circuit 52|, 3M, fili! between the source of electrical energy 300 and the motor operated feeder means 23, 25. The relay valve device 401 may be referred to as relay valve means responsive to pressure of uid in the first control pipe 5| 3 at or above the minimum pressure to connect the Isecond control pipe l52! either to atmosphere or to the supply pipe 5I5, respectively. The magnet valve device 40S might be referred to as magnet valve means energizable and de-energizable to establish connection between the supply pipe y5!5 and either the source of iiuid under pressure 5l5 or atmosphere via 336, respectively, and the switch 525 may be referred to as switch means opera-ble to establish and disestablish electrical circuit between the source of electrical energy 360 andthe magnet valve means 459.

Having now described the invention, what we claim as new and desire to secure by Letters Patent is:

1. In combination with a source of fluid under pressure, a source of electrical energy, a combustion chamber device, two independent sources of fuel, and two nozzle devices for introducing fuel into said combustion chamber device from said two sources of fuel, respectively, fuel conveying means for conveying fuel to one of said nozzle devices, motor operated feeder means for feeding fuel from one of said sources of fuel to said conveying means, a first control pipe, fuel iiow regulating means for regulating iiow of fuel from the other of said sources of fuel through the other nozzle device, between a maximum amount and a minimum amount in response to variation in pressure of iiuicl in said first control pipe between a maximum pressure and a minimum pressure, respectively, a fluid pressure supply pipe, an operators control valve device employing fluid under pressure from said supply pipe to effect said variation in pressure of fluid in said rst control pipe, a second control pipe, a pressure switch device responsive to pressurization and depressurization of said second control pipe to disestablish and establish, respectively, an electrical circuit between said source of electrical energy and said motor operated feeder means, relay valve means responsive to pressure of fluid in said first control pipe at or above said minimum pressure to connect said second -control pipe either to atmosphere or to said supply pipe, respectively, magnet valve means energiza'ble and `de-energizable to establish connection between said supply pipe and either said source of fluid under pressure or atmosphere, respectively, and switch means operable to establish and disestablish electrical circuit between said source of electrical energy and said magnet valve means to control energization thereof.

2. In combination with a uid pressure lsupply pipe, a source of electrical energy, a combustion chamber device, two independent sources of fuel, and two nozzle devices for introducing fuel into said combustion chamber devi-ce from said two fuel sources, respectively, by-pass Valve means having a chamber and being responsive to release or supply of fluid under pressure to and from said chamber to establish a fuel supply communication between one of said sources of fuel and the respective one of said nozzles or to by-pass said supply communication, respectively, a control pipe, fuel flow regulating means for regulating iioW of fuel from the other of said fuel sources to th-e respective other of said nozzle devices between a maximum amount and a minimum amount in response to variation in pressure of fluid in said control pipe between a maximum pressure and a minimum pressure respectively, a iluid pressure supply pipe, an operators control valve device employing fluid runder pressure from said supply pipe to effect said variation in pressure of uid in said control pipe, relay valve means responsive to pressure of fluid in said control pipe `at or above said minimum pressure to connect said chamber either to atmosphere or to said supply pipe, respectively, magnet valve means fenergizable and de-energizable to establish connection between said supply pipe and either said source of fluid under pressure or atmosphere, respectively, and switch means operable to establish and disestablish electrical circuit between said source of electrical energy and said magnet valve means.

HARRY C. MAY. ELLIS E. HEWITT.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,459,072 Peebles June 19, 1923 1,657,436 Munro Jan. 24, 1928 2,309,356 Peterson Jan. 26, 1943 2,354,999 Ladd Aug. 1, 1944 

